- Hello, Alina! How are you? Why are you looking so tired?
- Hello, I am really very tired today. I was in the forest where I skated a lot.
- Really? Are you fond of winter sport?
- Yes, I am. I do sport every two days. And what kind of winter sports are you fond of?
- I am fond of skiing most of all. In my opinion it's a very interesting sport.
- How interesting! How many times a week do you go to your trainings?
- Four times a week.
- And what other kinds of sports are you fond of?
- Besides it I like basketball, but sad to say I play it very badly.
- I also play basketball badly. I'm afraid "of any ball".
- Well, Alina. Let's say good-bye to each other, I have to hurry home.
- Ok, see you!
Dmitri Ivanovich Mendeleev is a famous Russian chemist. He is best known for his development of the properties of the chemical elements of the periodic table. This table shows that property elements change periodically when they are ordered by atomic weight. Mendeleev was born in 1834 in Tobolsk, Siberia. He studied chemistry at the University of Saint Petersburg and in 1859 he was sent to study at the University of Heidelberg. Mendeleev returned to St. Petersburg and became a Professor of Chemistry at the technical Institute in 1863. He became a Professor of General Chemistry at the University of Saint Petersburg in 1866. Mendeleev was a well-known teacher, and because there was not a good chemistry textbook at the time, he wrote in two volumes" principles of chemistry" which became a classic chemistry Textbook. In this book, Mendeleev tried to classify elements according to their chemical properties. In 1869, he published his first version of his periodic table of elements. In 1871, he published an improved version of the periodic table, in which he left spaces for elements that were not known at the time. His table and theories were later confirmed when three predicted elements: gallium, germanium, and scandium were discovered. Mendeleev investigated the chemical theory of solutions. He found that the Best proportions of alcohol and water in vodka are 40%. He also investigated the thermal expansion of liquids and the nature of oil. In 1893, he became Director of the Bureau of weights and measures in St. Petersburg. Petersburg and held this post until his death in 1907.
Объяснение:
надеюсь
